<?php
session_start();
/*
print_r($_SESSION['prijzen']);
echo "<hr>";
print_r($_SESSION['producten']);
echo "<hr>";
*/

//print_r($_GET);

$_SESSION['winkelwagen'][] = $_GET['productId'];

echo "<a href='webshop.php'>webshop</a>";

print_r($_SESSION['winkelwagen']);
?>